Whitefly, techniques and organic treatments to avoid them

Whitefly, tiny white insects with wings on the underside of a tomato leaf

Whiteflies are tiny insects that can attack all kinds of plants, particularly:

hibiscus, geraniums, greater celandine, fuchsia plants and certain vegetables from the vegetable patch such as tomatoes.

After forming a large colony under the leaves, these insects suck the sap of the plant and weaken it. They also make leaves sticky and cause sooty mold to appear.

A large-scale invasion can lead to the plant’s demise.

Conditions that favor the spread of whitefly

Greenhouse cultivation and strong heat waves are the main causes of whitefly appearing on plants.

How to fight whiteflies?

Traditional methods like insecticides or aphid treatments can be effective, even though they only target adult insects and don’t destroy eggs.
If those methods are applied, repeat treatment every 3 days over a 2 to 3 week period.
Be careful! These products are often dangerous to breath in.

Organic treatments against whitefly

  • Place whitefly traps. In specialized horticulture stores, you can find sticky glue that can be applied on any yellow surface, since whiteflies are attracted by that color.
  • Some predator insects can help eliminate them. A tiny wasp called Encarsia formosa does just that, since it lays its eggs inside whitefly larvae. Another predator is a bug called Macrolophus caliginosus that eats these parasites.
  • Don’t use predator insects inside your house.
  • Lastly, it is also possible to spray an insecticidal soap based on permethrin. This last solution has been proven to be efficient. In all above cases, you can bring infected plants to a cool room since these parasites need heat to develop.

Learn more about diseases

Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Tiny flies appear on leaves by Rosalyn & Gaspard Lorthiois, own work